{ "data": { "question": { "questionId": "100164", "questionFrontendId": "面试题 02.06", "categoryTitle": "LCCI", "boundTopicId": 45650, "title": "Palindrome Linked List LCCI", "titleSlug": "palindrome-linked-list-lcci", "content": "

Implement a function to check if a linked list is a palindrome.

\r\n\r\n

 

\r\n\r\n

Example 1:

\r\n\r\n
\r\nInput:  1->2\r\nOutput:  false \r\n
\r\n\r\n

Example 2:

\r\n\r\n
\r\nInput:  1->2->2->1\r\nOutput:  true \r\n
\r\n\r\n

 

\r\n\r\n

Follow up:
\r\nCould you do it in O(n) time and O(1) space?

\r\n", "translatedTitle": "回文链表", "translatedContent": "

编写一个函数，检查输入的链表是否是回文的。

\n\n

 

\n\n

示例 1：

\n\n
输入： 1->2\n输出： false \n
\n\n

示例 2：

\n\n
输入： 1->2->2->1\n输出： true \n
\n\n

 

\n\n

进阶：
\n你能否用 O(n) 时间复杂度和 O(1) 空间复杂度解决此题？

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= null\n * }\n */\nclass Solution {\n fun isPalindrome(head: ListNode?): Boolean {\n\n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Rust", "langSlug": "rust", "code": "// Definition for singly-linked list.\n// #[derive(PartialEq, Eq, Clone, Debug)]\n// pub struct ListNode {\n// pub val: i32,\n// pub next: Option>\n// }\n//\n// impl ListNode {\n// #[inline]\n// fn new(val: i32) -> Self {\n// ListNode {\n// next: None,\n// val\n// }\n// }\n// }\nimpl Solution {\n pub fn is_palindrome(head: Option>) -> bool {\n\n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "PHP", "langSlug": "php", "code": "/**\n * Definition for a singly-linked list.\n * class ListNode {\n * public $val = 0;\n * public $next = null;\n * function __construct($val) { $this->val = $val; }\n * }\n */\nclass Solution {\n\n /**\n * @param ListNode $head\n * @return Boolean\n */\n function isPalindrome($head) {\n\n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "TypeScript", "langSlug": "typescript", "code": "/**\n * Definition for singly-linked list.\n * class ListNode {\n * val: number\n * next: ListNode | null\n * constructor(val?: number, next?: ListNode | null) {\n * this.val = (val===undefined ? 0 : val)\n * this.next = (next===undefined ? null : next)\n * }\n * }\n */\n\nfunction isPalindrome(head: ListNode | null): boolean {\n\n};", "__typename": "CodeSnippetNode" }, { "lang": "Racket", "langSlug": "racket", "code": "; Definition for singly-linked list:\n#|\n\n; val : integer?\n; next : (or/c list-node? #f)\n(struct list-node\n (val next) #:mutable #:transparent)\n\n; constructor\n(define (make-list-node [val 0])\n (list-node val #f))\n\n|#\n\n(define/contract (is-palindrome head)\n (-> (or/c list-node? #f) boolean?)\n\n )", "__typename": "CodeSnippetNode" }, { "lang": "Erlang", "langSlug": "erlang", "code": "%% Definition for singly-linked list.\n%%\n%% -record(list_node, {val = 0 :: integer(),\n%% next = null :: 'null' | #list_node{}}).\n\n-spec is_palindrome(Head :: #list_node{} | null) -> boolean().\nis_palindrome(Head) ->\n .", "__typename": "CodeSnippetNode" }, { "lang": "Elixir", "langSlug": "elixir", "code": "# Definition for singly-linked list.\n#\n# defmodule ListNode do\n# @type t :: %__MODULE__{\n# val: integer,\n# next: ListNode.t() | nil\n# }\n# defstruct val: 0, next: nil\n# end\n\ndefmodule Solution do\n @spec is_palindrome(head :: ListNode.t | nil) :: boolean\n def is_palindrome(head) do\n\n end\nend", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"49.3K\", \"totalSubmission\": \"101.6K\", \"totalAcceptedRaw\": 49324, \"totalSubmissionRaw\": 101583, \"acRate\": \"48.6%\"}", "hints": [ "回文数在向前写和向后写时是相同的。如果你颠倒链表会怎样？", "用栈试试。", "假设你有链表的长度。你可以实现这个递归吗？", "在递归方法中（我们有链表的长度），中点是基线条件，即isPalindrome(middle)是true。节点x是紧挨着middle的左侧的一个节点：该如何检查x -> middle -> y是否形成回文？现在假设检查通过。前一个节点a又该如何检查？如果x -> middle -> y是回文，怎么检查a -> x -> middle -> y -> b是回文？", "回到前面的提示。记住：返回多个值的方法有很多。你可以用一个新类来实现。" ], "solution": null, "status": null, "sampleTestCase": "[1,2]", "metaData": "{ \r\n \"name\": \"isPalindrome\",\r\n \"params\": [\r\n { \r\n \"name\": \"head\",\r\n \"type\": \"ListNode\",\r\n \"dealloc\": false\r\n }\r\n ],\r\n \"return\": {\r\n \"type\": \"boolean\"\r\n }\r\n}", "judgerAvailable": true, "judgeType": "large", "mysqlSchemas": [], "enableRunCode": true, "envInfo": "{\"cpp\":[\"C++\",\"

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